Compensating for error-producing influences in electrical apparatus



Jan. 14, 1930. L, ANNER' 1,743,252

COMPENSATING FOR ERROR PRODUCING INFLUENCES IN ELECTRICAL APPARATUS Filed Aug. 19. 1925 k 5 I ATTORNE S.

Patented Jan. 14, 19550;

umrensmras Parana OFFICE HARRY L. TANNEB, OF BBOOKLYN, NEW YORK, ASSIGNORTO FORD INSTRUMENT COM- PANY, INCL, OF LONG ISLAND CITY,'NEW YORK, A CORPORATION OF NEW YORK COMPENSATING FOR ERROR-PRODUCING INFLUENCES IN ELECTRICAL APPARATUS 7 Application filed August 19, 1925. Serial No. 51,200.

This invention relates to means for compensating for error'producing influences in electrical apparatus included in appropriate circuits. The invention, while not restricted to any particular field, is, for example, peculiarly suited to embodiment in signal trans mission or other electrical systems, and more especially in such systems of the same general character as that disclosed in my co-pending application, Serial No. 724,912, filed July 8, 1924:. V

In the signal transmission systems of the character referred to, there are transmitters comprising armatures provided with commutators, from which polyphase currents of variable frequency may be taken by a plurality of uniformly spaced brushes. The latter are adapted to be moved around the axes of the armatures, and are connected by suitable conductors to receivers having movable members. Due to the effect of the residual magnetism in the receivers, or to other causes a lag of the movable members of the receivers behind the positions which they should occupy occurs.

It is a purpose of the present inventionto advance the phase relation in the circuit which supplies the receiver to compensate for the lag in the receiver. Moreover, as there 1s occasion to reverse the direction of operation of the transmitter, it transpires that the full error due to the lag does not immediately appear, but progresses definitely in accordance with a well-known law to its full value. The invention contemplates causing the compensation for the lagto follow the same law,

whereby as the lag increases the compensation therefor correspondingly increases, until the maximum lag has been reached, when the maximum compensationwill also have been attained.

In carrying out the invention, means are provided for setting the transmitter in accordance with a particular value it is desired to transmit, the receiver in circuit with the transmitter being responsive to the polyphase currents supplied to it from the adjustable brushes which bear on the commutator of the transmitter. Thus, the movable member of the receiver seeks to assume a position corresponding to the transmitter setting, but in opposition to the lag.

While the setting of the transmitter to a particular value is taking place, certain elements of the invention co-act to effect acorrective adjustment in the circuit, as between the brushes and the commutator in addition to the relative positioning thereof for the purpose of establishing the transmission of a selected value. Such corrective adjustment occurs proportionately to the lag develop- 1 correcting adjustment coincidentally with the attainment of the maximum. lag.

arrangement is provided whereby values may be set up in either an increasing or decreasing order, at will, the lag correction being introduced in proper proportion in either direction.

More complex circuits are susceptible to the incorporation of the invention therein, proment, there being means to terminate the lagvision being made to correct for phase lag in other devices in the same circuit, the cummulatlve arror 1n the receiver due to hysteresis, or other causes, being proportionately and entirely compensated for. Thus, devices in become manifest hereinafter are to be understood to be included in the present invention, and it will be apparent to those skilled in the art that various modifications of the illustrated form of the invention may be indulged in without departing from the spirit of the invention, as set forth in the appended claims. 1

Referring to the single figure of the drawing, a transmitter T is provided with a direct current armature 1, it being understood, of

course, that the armature coacts with a suitable field (not shown). The windin 2 of the armature is connected to the mutua y msulated se ments of a commutator 3, a plurality-of equl'clistantly spaced brushes 4, and 6 bearing on the commutator 3. These brushes are;carried by but insulated from a brush ring 7, which is rotatable about the axis of. the armature'l. I 5

To rotate the brushes to any desired position, a handle 8 of a crank is turned, thereby rotating a shaft 9 on which a circular dial 10 is secured. On one face of the dial 10, extendin around in a circumferential margin thereo are graduations, which, in. the present instance, read from 0 to 360, any of these graduations being adapted to be brought into register with an index 11. I

Also secured to the shaft 9 is a driving disk 12, against one face of which a cork or other pad 13, shown in dotted lines, frictionally bears. The pad 13 is aflixed to the lower end of a downturned portion, of a relatively light arm 14 which is resilientin the direction of the driving disk 12, but is otherwise rigid. At its opposite end, the arm 14 is secured to a double pronged pallet 15, which is pivotally mounted on a pin 16 that has one of its ends rigidly secured in a cam 17 comparatively near the periphery thereof; In actual practice, the arm 14 and the pin 16 would probably be of much less length, and the pallet 15 would very likely lie substantially against the adjacent face of the cam 17, but for clearness of illustration distortion of certain parts has been resorted to. a During the actuation of the handle 8, the pointed terminal of one or the other of the prongs 15 01115 is entered in a notchbetween successive teeth of a gear 18, which is aflixed ;to the hub, 19 of a bevel gear 20, the hub 19 bemg'pinned to the shaft 9. The gear 20 is amember 'of-a mechanical differential, wheref .m there 1s a. differential center comprising a spider 21 loosely-mounted on theshaft-9 and gears 22 and 23 revolublegon studsj carried;- by the spider; 'In mesh with the difierential center gears 22 and 23 is another differential n emberm the form of agear 24, which'is pinned t)- a shaft 25.

Fast on tli's shaft is a pinion 26giwliich meshes with teeth 27 on the periphery of the brush ring 7, whereby the turning of the crank handle 8 effects rotary adjustment of the brush ring 7 through the above outlined drive. Accompanying the rotary movement of the brush ring 7 is the consequent annular displacement of the brushes 4, 5 and 6, resulting in a positioning of them with'respect to the. commutator 3 which is represented by the graduation on the-dial 10 that is in register with the index 11.

v The brushes 4,!) and 6 are electrically connected' through conventionaly shown slip rings 28, 29 and 30, and by-conductors 31,- 32

' and 33 to equidistant p'ointsof a stator winding 34 of a receiver R, whereby the potential at these points corresponds to that o the in'the receiver B, there is a lag of the rotor 35 behind the position it should occupy to conform to the reading of the dial 10 against the index 11. Compensation is made for this lag by advancing the phase relation in the circuit which supplies the receiver, whereby the efiect of the lag is nullified, and the rotor 35 occupies a position truly indicative of the dial reading. v

That this may he brought about, the turning of the handle 8 at once causes the end of one, or the other of the prongs 15 or 15 to become embraced by the flanks of two adjacent teeth of the gear 18, whereupon the pallet 15 is'pushed by 'the gear 18, so that, acting through the pin 16,it.rotates the cam 17 ,which is loosely mounted on the shaft 9. A slight initial rotary movement of the pallet 15 about the pin 16 results in .the engagement of one of its prongs=by the teeth of the gear 18, the

its duration in the apparatus is established by the spacing of a pair of stops 36 and 37, between which the downturned portion of the arm 14 is adapted to swing, and by which the arm is arrested when the cam 17 has moved, in' one direction or .the other, an amount cor-Y responding-to the complete development of.-

the lag.

That the cam"17 may be effective coincidently with the lag development,its periphe has a portion that is given a contour whic conforms to the law that governs the progress'ion of the lag. The cam may be of any shape thatconforms to the referred to law,

and in practice the compensation may be introduced as a straight line function of'the angle through which the transmitter brushes are shifted before the maximum error occurs, since this will ordinarily be found to afioi'd a sufiicientlyclose approximation of the law to give satisfactory compensation. The portion of the periphery of the cam 17 which is effective for this purpose is synchronized with the'movement of the downturned portion of the arm 14.

A follower roller38'is pivoted at the upper end of alever arm 39 of a pivoted frame 40, and is held in close contact with the periphery of the cam 17- by a spring 41. The frame 40 is accordingly rocked by the cam, ,17 in accordance with the law that governs the development of the lag due to hysteresis, and has another lever arm 42, connected by a link 43 to a stud that projects from the spider 21 of the difierential. Obviously, as the cam 17 rocks the frame 40 in accordance with the law that overns the development of the lag, this frame through the link 43 correspondingly I turns the spider 21 and the center of the differential. Accordingly, the difierential member 24 is turned proportionately to the degree'of the cam actuation, and rotates the shaft 25 similarly, wherebythe pinion 26 turns the brush ring 7 and the brushes 4, 5 and 6. This brush displacement advances the phase relation in the circuit which supplies current to the receiver R, and so compensates for the lag due to hysteresis, in accordance with the law that governs the development of the lag. Consequently, the rotor is always in a position truly corresponding to the reading of the dial 10 against the index 11.

When making minor changes inthe setting of the dial 10, in either direction, it may occur that the downturned portion of the arm 14 will be shifted between the stops 36 and 37. but not sufiiciently to engage either stop. At such times, the frictional engagement between the driving disk 12 and the pad 13 remains undisturbed, so that the driving force that turns the dial 10 also acts through the disk 12, the pad 13, the arm 14, pallet 15 and the pin 16 to turn the cam 17 an amount corresponding to the angular displacement of the dial 10, the pallet 15 automatically reversing movable member of the receiver behind the position it should occupy in response to the setting ofthe dial 10. Such a condition is represented in a circuit branched from the previously described circuit by conductors 44, and 46, Which are connected to equidistant points of the stator 47 of an electrical differential of the type disclosed in the aforementioned co-pending application, Serial No. 254,738. The same points of the stator winding 47 are electrically connected to brushes- 48, 49 and 50, which bear on a commutator 51, the segments of which are connected electrically to, the winding 52 of the armature. whereby the armature is rotated. The armature is also provided with a direct current generator winding 53, which is connected to rotor 65 is responsive.

the segments of another commutator 54, against which brushes 55,56 and-57 hear, these brushes being carried by a brush ring 58'. Conductors lead from the brushes 55, 56 and 57 to conventionally shownslip rings 58, 59 and 60, from which other conductors 61, 62 and 63 extend to equidistant points of a stator 64'of a receiver R to which stator a It will be apparent that current will be conveyed from the brushes 4,5 and 6 of the transmitter T through the slip rings 28, 29 and 30, and the conductors'44, 45 and 46 to the equidistant points of the stator winding 47 with potentials corresponding to the positioning of the brushes '4, 5 and 6. The electrical connections from these points in the stator winding to the brushes 48, 49 and 50, the commutator 51 and the armature winding 52, cause the armature to be rotated. Direct current will then be generated in the other armature winding 53, and with the brushes 55, 56 and 57 hearing on the commutator 54 in positions corresponding to those in which the brushes 48, 49 and bear on the commutator 51, current will be carried through the .slip rings 58, 59 and and the conductors 61, 62 and 63 to the spaced points of the stator Winding 64. of the receiver R with potentials corresponding to the setting ofthe brushes 4, 5 and 6 of the-transmitter Under these conditions t-hedevice acts as a relay for supplying power to the system to provide for stronger receiver operation.

Ordinarily, there is no shifting of the brushes 55, 56 and 57, but such shifting may be eflected for the purpose of adjusting the indicator of the receiver with reference to the indicator of the transmitter to introduce corrections, or the like, ashereinafter explained in detail.

The rotor 65.0f the receiver R is subjected to the influence of the lag due to hysteresis both in the receiver and the electrical difl'erential, and in any other apparatus in which hysteresis can be present, which may be included in the circuit. It having already been shown how compensation is made for leg in the receiver of the first described circuit, and as it winding 69 of a correction motor 70, the current received by this stator winding from the transmitter T having potentials variable with and corresponding to the setting of the transmitter brushes 4, 5 and 6. Rotatively mounted within the stator winding 69 is a rotor 71 having a core 72 and a winding 73 disposed in slots therein in the usual manner,

the rotor winding being connected across direct current mains 74 and 75 by conductors 76 and 77, the rotors and 65 of the previously referred to receivers being also connected across these mains.

The rotor 71 of the correction motor 70 rotates continuously during the usual operation and is loosely mounted on a cylindrical portion of shaft 78, but rotates with the shaft during a period corresponding to the length of time the lag due to hysteresis in the electrical differential takes to develop to its maximum. Such concomitant rotation of the rotor 71 and the shaft 78 is occasioned by a frictional clutch arrangement wherein a washer 79 is pressed against one end of the rotor core 72 by a spring 80, one end of which bears against acollar 81 on the shaft 78, the other end of the spring pushing against the washer 79. A portion of the shaft 78 is square, or non-circular, and passes through a central squarelhole in the washer 79, extending toward the collar- 81 Thus, as'the washer is frictionally driven by the rotor core 72 the walls of'its square central hole rotate the square portion of the shaft 78..

Also mounted on the shaft 78 is an arm 82 that is affixed to and moves with the shaft 78 until it engages one or the other of stops 36' and 37 which correspond to the stops 36 and 37 of the previously described correction device. The spacing of the stops 36 and 37' from each other permits movement of the arm 82 through a distance corresponding to a period required for the maximum lag in the electrical differential to develop. At the end of such period, the arm 82 is arrested by either the stop 36' or 37', whereupon the shaft 78 ceases to rotate, and the yieldingly pressed washer 79 permits a slippage between itself and the rotor core 72, so that the rotor 71 continues to spin. The compensation for the lag in the electrical differential due to hysteresis is in proportion to the movement of the shaft 78, which has a pinion 83 affixed thereto. The pinion 83 drives a gear 84 on a shaft 85, which also carries a pinion 86, which drives a gear 87 mounted on a shaft 88. This shaft has the spider 89 of a mechanical differential pinned to it whereby the center of this differential is moved by an amount to compensate for the lag due to hysteresis in the electrical differential.

Since a gear 90, which is-another member of the mechanical differential, is normally' stationary, a further member of thedifferential, shown as a gear 91, moves in response to the actuation of the spider 89 and its gears 92 and 93. As a result, a shaft 94, on which the differential gear 91 is-secured, turns, and

"with it a pinion 95 aflixed to its opposite end.

The pinion 95 is in mesh with teeth on the periphery of the brush ring 58', so that the corrective movement in reaching the pinion 95 is also imparted to the brush ring 58'.

Movement of the latter angularly displaces the brushes 55, 56 and 57 with respect to the commutator 54, whereby the phase relation in the circuit which supplies the receiver is advanced to compensate for the lag in the electrical differential due tohysteresis.

Compensation being made for the lag both inthe electrical differential and the-receiver, as set forth, the rotor of the receiver willassume a position truly indicative of the setting of the dial of the transmitter.

A handle 96 operates a crank anda shaft 97, 011 which is mounted a dial 98 that is graduated to read against an index 99, whereby corrections may be put into the electrical differential. When the dial 98 is set, gears 100 are turned by the rotation of the shaft 97',

thus turning a sleeve 101, which constitutes the hub of the gear 90. As the latter turns, it actuates the gears 92 and 93 of the differential center without rotating such center,

thereby turning the differential gear 91, the

shaft 94, pinion 95 and brush ring 58', thus shifting the brushes 55, 56 and 57 on the commutator 54, to effect the desired corrections.

Any number of devices which develop lag due to hysteresis or other causes, may be in circuit, and be compensated for in accordance with the principles herein set forth, the specific embodiment of the invention disclosed being merely illustrative of one of a variety 7 of ways in which the practiced.

I claim: 1

1. In combination, an electrical circuit having a transmitter and a receiver the-rein in a phase relation tending to -maintain POSI- tional coincidence of the transmitter and reinvention may be ceiver, said receiver being subject to error producing influences developing; in accordance with naturallaw, and means predeterminedly operable in accordance withsuch natural law to change the phase relation in the circuit to compensate for the effect on the receiver of said influences.

2. In combination, a transmitter, a receiver responsive to the transmitter and subject to error produclng influences and means operable substantially according to predetermined law to'effect said transmitter to compensate J.

for the effect on the receiver of said influences.

3. In comb1nat1on,a transmltter, a recelver responsive to the transmitter and subject to 'by the movable part of the latter is displaced by operation of said transmitter, means for governing ject to hysteresis,

predeterminedly setting said transmitter, and means controlled to act proportionately to predetermined variations for automatically modifying the resultant displacement of the movable part of the receiver. 4

5. In combination, a transmitter, a receiver, circuit connections therebetween whereby said receiver is responsive to said transmitter, and means controlling said transmitter operable to set the same selectively and correctively, the corrective setting being under predetermined control'and made proportionately to the error, to effect a corrected response of the receiver to thesetting of said transmitter.

6. In combination, an electrical circuit having therein a receiver subject to hysteresis, and means operable substantially in ac cordance with the law governing lag due to hysteresis to advance the phase relation in the circuit to compensate for lag in the receiver due tohysteresis.

7-. In a combination, an electrical circuit, apparatus therein operable in response to variable polyphase currents and corrective means operable in accordance with the law the development of lag in said and adapted to advance the phase apparatus the circuit to compensate for the relation in lag.

8. In combination, a polyphase circuit adapted to be energized by currents of variable frequencies, a receiver in circuit therewith responsive to changes in frequency and suband means operable substantially in accordance with the law governing the development of lag due to hysteresis tween said source of current and said circuit.

to advancethephase relation in the circuit to icompensate for the la in'the receiver.

9. In combination, an electrical circuit, a

receiver therein subject to hysteresis, means to supply polyphase currents to the receiver, and a phase-altering means operable substantially in accordance with the law governing the development of hysteresis and adapted to actuate the first named means to change the phase relation inthe circuit to compensate for the effect of hysteresis in the receiver. 10. In combination, a source of direct current supply, a polyphase circuit, an electrical connection between said source supply and said circuit adjustable to vary the frequency of the current, a receiver in the circuit subject to hysteresis, and automatic means including a control governing said means" substantially in accordance with the law by which hysteresis developst'o adjust said connection to advance the phaserelatioh in the circuit to compensate for the effects of hysteresis in the receiver. 11. In combination, a source of electrical current, a polyphase circuit, a connection beadjustable to vary the frequency of the current, a receiver in the circuit subject to of current hysteresis, other, apparatus in the circuit also subject to hysteresis, and means including a control governing said means in accordance with the law by which hysteresis develops to advance the phase relation in the circuit to compensate for the effects of hysteresis in both said receiver and said other apparatus.

12. In a transmission system, a transmitter for. generating polyphase current of variable frequency, a receiver operable thereby and subject tohysteresis, mechanism for selectively setting said transmitter, and means controlled in substantial accordance with the law governing the development of hysteresis and being operable to modify the setting of said transmitter in accordance with lag in the receiver due to hysteresis.

13. Ina transmission system, a transmitter for generating polyphase current of variable frequency, a receiver operable thereby and subject to hysteresis, mechanism' for selectively setting said transmitter, and means controlled in substantial accordance with the law governing the development; of hysteresis and'operable with said mechanism to modify the setting of said transmitter proportionately to and to nullify the eifect of hysteresis in said receiver.

14. In a transmission system, a transmitter for generating polyphase current of variable frequency, a receiver subject to hysteresis, mechanism for selectively setting said transmitter, and corrective meansfor compensating for the eifects of hysteresis in said receiver said means being operable with said mechanism under predetermined'control so as to-be actuated in accordance with the degree of hysteresis.

15. In a transmission system, a transmitter for generating polyphase current of variable frequency, a receiver responsive thereto and subject to hysteresis, mechanism for setting said transmitter, corrective means under predetermined control in accordance with the law governing lag due to hysteresis for compensating for the effects of hysteresis in said receiver and o erable by said mechanism, and means to e ect cessation of operation of said corrective means upon its compensation for the hysteresis.

16. In aitransmission system, a transmitter for generating polyphase current of variable frequency, a receiver responsive thereto and subject to hysteresis, mechanism for setting said transmitter, means subject to hyoperable thereby and ste'resis interposed between the transmitter and receiver for changing the phase relation of the current in the receiver with respect to tive means associated with said receiver, the

different corrective means acting to compensate for the effects of hysteresis in said inter osed means and the receiver.

1 In a transmission system, a transmitter for generating polyphase current of variable frequency, a receiver'responsive there-f to and mechanlsm comprising a plurality of elements, correlated for operating said transmitter, certain of said elements acting under predetermined control in accordance with the law governing hysteresis to intro duce compensation for hysteresis insaid receiver.

18. In a transmission system, a transmitter for fgenerating polyphase current of varisaid brushes comprising elements co-acting to normally set said brushes, certain of said elements modifyingthe setting of said brushes proportionately. to the presence of hysteresls in said receiver.

20. In a transmission system, a transmitter for generating polyphase current and having a communtator and brushes therefor adjustable thereabout, a receiver responsive to said transmitter, means for controlling said brushes operable to normally" set the latter and including partsoperable in ac cordance with the rate of development of hysteresls in said receiver tomodify the set.- tmg of said brushes to compensate therefor, an means to arrest the action of. said parts upon full compensation for the hysteresis.

21. In a transmission s stem, a. transmitter for generating polyphase current and having a commutator and brushes therefor ad ustable thereabout, receiver responsive to sald transmitter, means for controlling said brushes operable to normally set the same and having a correction element, a differem tlal and an operating connection from the element thereto, said element operating said difi'erential proportionately to the development of hysteresis to move said brushes to compensate therefor.-

22. In a transmission system, a transmitter' forgenerating polyphase current and aving a commutator and brushes adjustable thereabout, a receiver responsive to said transmitter, means controlling: said brushes operable to normally set the same and in-' cludinga correction element, means to limit the extent of its action, a differential and an-operatin connection from said element.

thereto, sai element operating said difl'erential to} move said brushes to compensate therea out, receiving means res onsive to 5 said transmitter, means contro brushes adapted to normally set the same and including an operating part, a correction element, a driving-connection between said part, an element subject to interruption, a differential controlled by said correction element to modiiythe position of said brushes to compensate for the effect of hysteresis in said receiving means, and means to -efl"ect interruption of said driving connection upon thecompletion of the compensation'.

In testimony whereof I aflix my signature.

HARRY L. TANNER.

ing said- YDIISO-LAIMER 1,743,252.Ha1-ry L. Tanner, Brooklyn, N. Y. COMPENSATING FOR ERROR-PRODUC- ING INFLUENCES IN ELECTRICAL APPARATUS. Patent dated January 14, 1930.

Disclaimer filed October 3, 1930, by the assignee, F 0rd Instrument 00mpang ,lnc.

Disclaims from the scope or meaning ofclaims 2 and 4 of said Patent #1,743,252, any purpose or use of the apparatus defined in these claims other than its application to the compensation for the influence of hysteresis on the receiver.

[Official Gazette October 21, 1930.]

-DISO-I AIM'ER 1,743,252.Hwr-rg L. Tanner, Brooklyn, N; Y. COMPENSATING FOR ERROR-PRODUC- ING INFLUENCES IN ELECTRICAL APPARATUS. Patent dated January 14, 1930.- Disclaimer filed October 3, 1930, by the assignee, Ford Instrument O'o m 3 pany, Inc. h I Disclaim's from the scope or meaning ofclaims 2 and 4 of said Patent #1,743,252, any purpose or use of the apparatus defined in-these claims other than its application to the compensation for the influence of hysteresis 0n the receiver.

[Ofli'cial Gazette October 21, 1930.] 

